Answer:
Step-by-step explanation:
- Let the speed of the boat be x
- Speed against the current in the river is x - 2
Time in the river:
Time in the lake:
The difference:
Solve for x to find the speed of the boat
Multiply both sides by x(x - 2) to clear the fraction:
- 6x = 15(x - 2) - x(x - 2)
- 6x = 15x - 30 - x² + 2x
- x² - 11x + 30 = 0
- (x - 5)(x - 6) =0
- x -5 = 0, x - 6 = 0
- x = 5 km/h, x = 6 km/h